Abstract: Grass mixed intercropping with legume is considered the most important planting pattern in establishing artificial grasslands in alpine regions,and intercropping is a classical planting pattern to improve the crops productivity and land utilization efficiency of agricultural systems. However,the effect of mixed and intercropped planting patterns on seed yields of Avena sativa and Pisum sativum was unclear. Therefore,we conducted a field study to examine the effect of nitrogen addition on forage and seed yields of A. sativa and P. sativum with monocultured,mixed and alternate-row intercropped planting patterns. Our results showed that nitrogen addition significantly improved the above- and belowground biomass of monocultured A. sativa and P. sativum in mixed and alternate-row intercropped system. Both above- and belowground biomass of alternate-row intercropping system was highest under the same nitrogen addition level;by contrast,monocultured P. sativum was lowest. Similarly,nitrogen addition also significantly enhanced the seed yield of A. sativa;high nitrogen addition level has a positive effect on seed yields of monocultured P. sativum,and a negative effect was detected on seed yields of P. sativum in mixed and alternate-row intercropped system. There is no significant difference in seed yields of A. sativa among monocultured,mixed and alternate-row intercropped systems under low nitrogen addition level. Furthermore,eithor A. sativa or P. sativum partial and overall land equivalent ratio in alternate-row intercropped system was higher than mixed intercropped system,the nitrogen addition significantly enhanced partial land equivalent ratio of A. sativa while decreased it for P. sativum. In addition,competition ratio of A. sativa in mixed and alternate-row intercropped system were significantly stronger than P. sativum;nitrogen addition also enhanced the competition ratio of A. sativa,by contrast,competition ratio of P. sativum reduced. In conclusion,low nitrogen fertilizer had a positive role on improving productivity of A. sativa and P. sativum in mixed or alternate-row intercropped systems,and our findings suggested that A. sativa alternate-row intercropped with P. sativum combining with low nitrogen fertilizer addition should be recommended in establishing high productivity and quality artificial grasslands in alpine regions.

Key words: Avena sativa, Pisum sativum, mixed intercropping, alternate-row intercropping, forage yield, seed yield, nitrogen addition

摘要： 禾豆间作是农作物增产和提高土地利用效率的经典种植方式，有关燕麦(Avena sativa)与豌豆(Pisum sativum)不同间作种植模式对饲草和种子产量影响的研究较少。本研究开展氮添加对燕麦与豌豆单播、同行混合及隔行间作三种植模式饲草和种子产量的影响。结果表明：(1)氮添加能增加单播、同行混合和隔行间作系统燕麦和豌豆的生物量，相同氮水平下，隔行间作系统生物量最高；同时，氮添加能提高单播、间作燕麦及单播豌豆种子产量。(2)隔行间作燕麦和豌豆的土地当量比高于同行混合间作模式。(3)同行混合和隔行间作燕麦的竞争系数显著高于豌豆。由此可见，燕麦和豌豆隔行间作种植并适量氮素添加是实现高寒区人工草地增产提质的有效途径。

关键词: 燕麦, 豌豆, 同行混合间作, 隔行间作, 种子产量, 氮添加